Expandable cellular structures that are often used as honeycomb window shades consisting of a plurality of elongated tubular cells are well known in the art. Honeycomb window shades provide consumers with numerous advantages in window coverings such as improved insulation, light filtering, and aesthetic appeal. The present invention relates to cellular structures and a method for making the cellular structures that utilizes a novel system of cutting, folding, gluing and arranging strips of fabric material in the construction of honeycomb panels.
The cells within such cellular honeycomb structures are constructed of a flexible material with each cell extending across the width of the structure and in a parallel relationship to the other cells. The volume occupied by each cell is decreased or expanded, respectively, by collapsing the cells together or spreading them apart. The expandable attributes of the cells provides a useful structure for covering areas of various sizes.
Many of the current cellular structures have pleats extending along the length of each cell. The pleats are generated by placing creases in the material during cell fabrication. The pleats assist in the orderly collapsing of individual cells as the structure is compressed. The pleats also result in the face and back of the structure having a corrugated appearance which is similar to that of an accordion.
One shortcoming experienced with standard honeycomb shade constructions that results in an undesired aesthetic appearance is due to the way honeycomb shades achieve their shape. Typically, honeycomb blinds are comprised of creased and folded lengths of material. The folded lengths of materials have a spring coefficient that prevents the folded material from completely stretching out, and thereby maintaining the pleated or honeycombed appearance.
Because the structure of the honeycomb structure is based on the spring coefficient of the material, however, the overall appearance of a conventional honeycomb panel is affected by the varying amount of weight supported by any particular cell of the honeycomb panel. Cells of the honeycomb panel that are located towards the top of the shade must support the weight of all the material below it and are stretched much more than cells located towards the bottom of the shade, which have less weight to support. As such, the predominance of the pleats emanating from those cells towards the top of the structure will gradually diminish as the amount of weight being supported by each cell increases. Thus, the cellular structure will fail to provide a uniformly distributed pleated appearance. The top cells will appear almost flat while the bottom cells will remain substantially pleated. The result of this is an uneven appearance and uneven shading ability of the blind. Over time, the cells towards the top of a shade may also be stretched such that the material loses its ability to retain a creased or pleated appearance.
The inability of a typical honeycomb cellular structure to limit the extent particular cells may be stretched also results in a waste of material. This is because with conventional honeycomb constructions a balance must be achieved with the cellular structure such that cells towards the top of the shade are not overly distorted while still allowing cells towards the bottom of the shade to extend sufficiently to provide a desirable aesthetic appearance. Often, a compromise is made such that honeycomb cells towards the bottom of a shade are not fully extended by a heavier weight to prevent cells at the top of the shade from being too stretched out. As a result, more cells will be needed to cover a window space than would be necessary if cells at the bottom of the shade could be fully extended. As a result, the material costs of providing additional rows of honeycomb cells than would otherwise be necessary to cover a window are increased.
Another shortcoming presented by most cellular honeycomb window shades is due to the fact that they are made with a single type of material is used throughout the window shade. This lack of flexibility in the ability to choose from different fabrics to provide different coloring, shading, and insulation combinations is simply not possible with shades constructed from a single type of material.
Accordingly, what is needed is a cellular structure as used in a honeycomb window shade that preferably maintains its pleated appearance from top to bottom when it is fully extended. The cellular structure of the window shade should be designed such that the cells collapse repeatably the same way to provide for a uniform and desirable appearance. What is further desired is a method of making a cellular honeycomb structure, wherein the shade constructed limits the amount any particular cell may be stretched and enables all the cells to be fully extended and provide a uniform appearance without the shortcomings of typical honeycomb blind structures. What is further desired is a window shade that offers the flexibility to choose different combinations of types of material for the shade. The present invention meets these desires.